We have the following DAGCombiner transformations:
(mul (shl X, c1), c2) -> (mul X, c2 << c1)
(mul (shl X, C), Y) -> (shl (mul X, Y), C)
(shl (mul x, c1), c2) -> (mul x, c1 << c2)
Usually the constant shift is optimised by SelectionDAG::getNode when it is
constructed, by SelectionDAG::FoldConstantArithmetic, but when we're dealing
with vectors and one of those vector constants contains an undef element
FoldConstantArithmetic does not fold and we enter an infinite loop.
Fix this by making FoldConstantArithmetic use getNode to decide how to fold each
vector element, the same as FoldConstantVectorArithmetic does, and rather than
adding the constant shift to the work list instead only apply the transformation
if it's already been folded into a constant, as if it's not we're going to loop
endlessly. Additionally add missing NoOpaques to one of those transformations,
which I noticed when writing the tests for this.
Differential Revision: https://reviews.llvm.org/D26605
llvm-svn: 287766
Add basic ComputeNumSignBits support for TRUNCATE ops for cases where the source's number of sign bits overlaps with the truncated size.
Improves X86 SIGN_EXTEND_IN_REG vector cases which were needlessly sign extending boolean vector results.
Differential Revision: https://reviews.llvm.org/D26851
llvm-svn: 287635
Currently computeKnownBits returns the common known zero/one bits for all elements of vector data, when we may only be interested in one/some of the elements.
This patch adds a DemandedElts argument that allows us to specify the elements we actually care about. The original computeKnownBits implementation calls with a DemandedElts demanding all elements to match current behaviour. Scalar types set this to 1.
The approach was found to be easier than trying to add a per-element known bits solution, for a similar usefulness given the combines where computeKnownBits is typically used.
I've only added support for a few opcodes so far (the ones that have proven straightforward to test), all others will default to demanding all elements but can be updated in due course.
DemandedElts support could similarly be added to computeKnownBitsForTargetNode in a future commit.
This looked like this had caused compile time regressions on some buildbots (and was reverted in rL285381), but appears to have just been a harmless bystander!
Differential Revision: https://reviews.llvm.org/D25691
llvm-svn: 285494
Currently computeKnownBits returns the common known zero/one bits for all elements of vector data, when we may only be interested in one/some of the elements.
This patch adds a DemandedElts argument that allows us to specify the elements we actually care about. The original computeKnownBits implementation calls with a DemandedElts demanding all elements to match current behaviour. Scalar types set this to 1.
The approach was found to be easier than trying to add a per-element known bits solution, for a similar usefulness given the combines where computeKnownBits is typically used.
I've only added support for a few opcodes so far (the ones that have proven straightforward to test), all others will default to demanding all elements but can be updated in due course.
DemandedElts support could similarly be added to computeKnownBitsForTargetNode in a future commit.
Differential Revision: https://reviews.llvm.org/D25691
llvm-svn: 285296
As noted in:
https://reviews.llvm.org/D25685
This is the next-to-smallest step needed to enable the ComputeNumSignBits fix in that patch.
In a minor attempt to keep some structure, we're pulling the FP helper over along with its
integer sibling, but clearly we can and should do more refactoring of the similar helper
functions in DAGCombiner and SelectionDAG to simplify and not duplicate functionality.
llvm-svn: 284421
SelectionDAG::getConstantPool will automatically determine an appropriate alignment if one is not specified. It does this by querying the type's preferred alignment. This can end up creating quite a lot of padding when the preferred alignment for vectors is 128.
In optimize-for-size mode, it makes sense to instead query the ABI type alignment which is often smaller and causes less padding.
llvm-svn: 284381
Masked-expand-load node represents load operation that loads a variable amount of elements from memory according to amount of "true" bits in the mask and expands the loaded elements according to their position in the mask vector.
Right now, the node is used in intrinsics for VEXPAND* instructions.
The work is done towards implementation of masked.expandload and masked.compressstore intrinsics.
Differential Revision: https://reviews.llvm.org/D25322
llvm-svn: 283694
Summary: Both computeKnownBits and ComputeNumSignBits can now do a simple
look-through of EXTRACT_VECTOR_ELT. It will compute the result based
on the known bits (or known sign bits) for the vector that the element
is extracted from.
Reviewers: bogner, tstellarAMD, mkuper
Subscribers: wdng, RKSimon, jyknight, llvm-commits, nhaehnle
Differential Revision: https://reviews.llvm.org/D25007
llvm-svn: 283347
With D24253 we can now use SelectionDAG::SignBitIsZero with vector operations.
This patch uses SelectionDAG::SignBitIsZero to recognise that a zero sign bit means that we can use a sitofp instead of a uitofp (which is not directly support on pre-AVX512 hardware).
While AVX512 does provide support for uitofp, the conversion to sitofp should not cause any regressions.
Differential Revision: https://reviews.llvm.org/D24343
llvm-svn: 281852
Summary:
An IR load can be invariant, dereferenceable, neither, or both. But
currently, MI's notion of invariance is IR-invariant &&
IR-dereferenceable.
This patch splits up the notions of invariance and dereferenceability at
the MI level. It's NFC, so adds some probably-unnecessary
"is-dereferenceable" checks, which we can remove later if desired.
Reviewers: chandlerc, tstellarAMD
Subscribers: jholewinski, arsenm, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D23371
llvm-svn: 281151
Add the ability to computeKnownBits and SimplifyDemandedBits to extract the known zero/one bits from BUILD_VECTOR, returning the known bits that are shared by every vector element.
This is an initial step towards determining the sign bits of a vector (PR29079).
Differential Revision: https://reviews.llvm.org/D24253
llvm-svn: 280927
If we are extracting a subvector that has just been inserted then we should just use the original inserted subvector.
This has come up in certain several x86 shuffle lowering cases where we are crossing 128-bit lanes.
Differential Revision: https://reviews.llvm.org/D24254
llvm-svn: 280715
Summary:
This greatly simplifies our handling of SDNode::SubclassData.
NFC, hopefully. :)
See discussion in D23035 for discussion about the design API of these
bitfields.
Reviewers: chandlerc
Subscribers: llvm-commits, rnk
Differential Revision: https://reviews.llvm.org/D23036
llvm-svn: 279537
This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.
llvm-svn: 278902
[DAG] Check debug values for invalidation before transferring and mark
old debug values invalid when transferring to another SDValue.
This fixes PR28613.
Reviewers: jyknight, hans, dblaikie, echristo
Subscribers: yaron.keren, ismail, llvm-commits
Differential Revision: https://reviews.llvm.org/D22858
llvm-svn: 277135
Summary:
Instead, we take a single flags arg (a bitset).
Also add a default 0 alignment, and change the order of arguments so the
alignment comes before the flags.
This greatly simplifies many callsites, and fixes a bug in
AMDGPUISelLowering, wherein the order of the args to getLoad was
inverted. It also greatly simplifies the process of adding another flag
to getLoad.
Reviewers: chandlerc, tstellarAMD
Subscribers: jholewinski, arsenm, jyknight, dsanders, nemanjai, llvm-commits
Differential Revision: http://reviews.llvm.org/D22249
llvm-svn: 275592
Summary:
Previously we took an unsigned.
Hooray for type-safety.
Reviewers: chandlerc
Subscribers: dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D22282
llvm-svn: 275591
For the most part this simplifies all callers. There were two places in X86 that needed an explicit makeArrayRef to shorten a statically sized array.
llvm-svn: 274337
Recommiting after correcting over-eager Debug Value transfer fixing PR28270.
[DAG] Previously debug values would transfer debuginfo for the selected
start node for a replacement which allows for debug to be dropped.
Push debug value transfer to occur with node/value replacement in
SelectionDAG, remove now extraneous transfers of debug values.
This refixes PR9817 which was being incompletely checked in the
testsuite.
Reviewers: jyknight
Subscribers: dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D21037
llvm-svn: 273585
Recommiting after fixing over-aggressive assertion
[DAG] Previously debug values would transfer debuginfo for the selected
start node for a replacement which allows for debug to be dropped.
Push debug value transfer to occur with node/value replacement in
SelectionDAG, remove now extraneous transfers of debug values.
This refixes PR9817 which was being incompletely checked in the
testsuite.
Reviewers: jyknight
Subscribers: dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D21037
llvm-svn: 273456
The setCallee function will set the number of fixed arguments based
on the size of the argument list. The FixedArgs parameter was often
explicitly set to 0, leading to a lack of consistent value for non-
vararg functions.
Differential Revision: http://reviews.llvm.org/D20376
llvm-svn: 273403
[DAG] Previously debug values would transfer debuginfo for the selected
start node for a replacement which allows for debug to be dropped.
Push debug value transfer to occur with node/value replacement in
SelectionDAG, remove now extraneous transfers of debug values.
This refixes PR9817 which was being incompletely checked in the
testsuite.
Reviewers: jyknight
Subscribers: dblaikie, llvm-commits
Differential Revision: http://reviews.llvm.org/D21037
llvm-svn: 272792
This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.
llvm-svn: 272512
As suggested by clang-tidy's performance-unnecessary-copy-initialization.
This can easily hit lifetime issues, so I audited every change and ran the
tests under asan, which came back clean.
llvm-svn: 272126
There are at least 2 places (DAGCombiner, X86ISelLowering) where this could be used instead
of ad-hoc and watered down code that is trying to match a power-of-2 pattern.
Differential Revision: http://reviews.llvm.org/D20439
llvm-svn: 270073
It's awkward to force callers of SelectNodeTo to figure out whether
the node was morphed or CSE'd. Update uses here instead of requiring
callers to (sometimes) do it.
llvm-svn: 269235
Summary:
When SelectionDAG performs CSE it is possible that the context's source
location is different from that of the selected node. This can lead to
incorrect line number records. We update the debug location to the
one that occurs earlier in the instruction sequence.
This fixes PR21006.
Reviewers: echristo, sdmitrouk
Subscribers: jevinskie, asl, llvm-commits
Differential Revision: http://reviews.llvm.org/D12094
llvm-svn: 268323
Summary:
Historically, we had a switch in the Makefiles for turning on "expensive
checks". This has never been ported to the cmake build, but the
(dead-ish) code is still around.
This will also make it easier to turn it on in buildbots.
Reviewers: chandlerc
Subscribers: jyknight, mzolotukhin, RKSimon, gberry, llvm-commits
Differential Revision: http://reviews.llvm.org/D19723
llvm-svn: 268050
visitAND, when folding and (load) forgets to check which output of
an indexed load is involved, happily folding the updated address
output on the following testcase:
target datalayout = "e-m:e-i64:64-n32:64"
target triple = "powerpc64le-unknown-linux-gnu"
%typ = type { i32, i32 }
define signext i32 @_Z8access_pP1Tc(%typ* %p, i8 zeroext %type) {
%b = getelementptr inbounds %typ, %typ* %p, i64 0, i32 1
%1 = load i32, i32* %b, align 4
%2 = ptrtoint i32* %b to i64
%3 = and i64 %2, -35184372088833
%4 = inttoptr i64 %3 to i32*
%_msld = load i32, i32* %4, align 4
%zzz = add i32 %1, %_msld
ret i32 %zzz
}
Fix this by checking ResNo.
I've found a few more places that currently neglect to check for
indexed load, and tightened them up as well, but I don't have test
cases for them. In fact, they might not be triggerable at all,
at least with current targets. Still, better safe than sorry.
Differential Revision: http://reviews.llvm.org/D19202
llvm-svn: 267420
Removed some unused headers, replaced some headers with forward class declarations.
Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'
Patch by Eugene Kosov <claprix@yandex.ru>
Differential Revision: http://reviews.llvm.org/D19219
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
This code was specific to vector operations with scalar operands:
all the opcodes in FoldValue (via FoldConstantArithmetic) can't
match those criteria.
Replace it with an assert if that ever changes: at that point,
we might need to add back a splat BUILD_VECTOR.
llvm-svn: 266100
In Memcpy lowering we had missed a dependence from the load of the
operation to successor operations. This causes us to potentially
construct an in initial DAG with a memory dependence not fully
represented in the chain sub-DAG but rather require looking at the
entire DAG breaking alias analysis by allowing incorrect repositioning
of memory operations.
To work around this, r200033 changed DAGCombiner::GatherAllAliases to be
conservative if any possible issues to happen. Unfortunately this check
forbade many non-problematic situations as well. For example, it's
common for incoming argument lowering to add a non-aliasing load hanging
off of EntryNode. Then, if GatherAllAliases visited EntryNode, it would
find that other (unvisited) use of the EntryNode chain, and just give up
entirely. Furthermore, the check was incomplete: it would not actually
detect all such potentially problematic DAG constructions, because
GatherAllAliases did not guarantee to visit all chain nodes going up to
the root EntryNode. This is in general fine -- giving up early will just
miss a potential optimization, not generate incorrect results. But, for
this non-chain dependency detection code, it's possible that you could
have a load attached to a higher-up chain node than any which were
visited. If that load aliases your store, but the only dependency is
through the value operand of a non-aliasing store, it would've been
missed by this code, and potentially reordered.
With the dependence added, this check can be removed and Alias Analysis
can be much more aggressive. This fixes code quality regression in the
Consecutive Store Merge cleanup (D14834).
Test Change:
ppc64-align-long-double.ll now may see multiple serializations
of its stores
Differential Revision: http://reviews.llvm.org/D18062
llvm-svn: 265836
Change isConsecutiveLoads to check that loads are non-volatile as this
is a requirement for any load merges. Propagate change to two callers.
Reviewers: RKSimon
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18546
llvm-svn: 265013
When merging stores in DAGCombiner, add check to ensure that no
dependenices exist that would cause the construction of a cycle in our
DAG. This may happen if one store has a data dependence on another
instruction (e.g. a load) which itself has a (chain) dependence on
another store being merged. These stores cannot be merged safely and
doing so results in a cycle that is discovered in LegalizeDAG.
This test is only done in cases where Antialias analysis is used (UseAA)
as non-AA store merge candidates will be merged logically after all
loads which have been checked to not alias.
Reviewers: ahatanak, spatel, niravd, arsenm, hfinkel, tstellarAMD, jyknight
Subscribers: llvm-commits, tberghammer, danalbert, srhines
Differential Revision: http://reviews.llvm.org/D18336
llvm-svn: 264461
This re-applies r262886 with a fix for 32 bit platforms that have 8 byte
pointer alignment, effectively reverting r262892.
Original Message:
Currently some SDNode operands are malloc'd, some are stored inline in
subclasses of SDNode, and some are thrown into a BumpPtrAllocator.
This scheme is complex, inconsistent, and makes refactoring SDNodes
fairly difficult.
Instead, we can allocate all of the operands using an ArrayRecycler
that wraps a BumpPtrAllocator. This keeps the cache locality when
iterating operands, improves locality when iterating SDNodes without
looking at operands, and vastly simplifies the ownership semantics.
It also means we stop overallocating SDNodes by 2-3x and will make it
simpler to fix the rampant undefined behaviour we have in how we
mutate SDNodes from one kind to another (See llvm.org/pr26808).
This is NFC other than the changes in memory behaviour, and I ran some
LNT tests to make sure this didn't hurt compile time. Not many tests
changed: there were a couple of 1-2% regressions reported, but there
were more improvements (of up to 4%) than regressions.
llvm-svn: 262902
Looks like the largest SDNode is different between 32 and 64 bit now,
so this is breaking 32 bit bots. Reverting while I figure out a fix.
This reverts r262886.
llvm-svn: 262892
Currently some SDNode operands are malloc'd, some are stored inline in
subclasses of SDNode, and some are thrown into a BumpPtrAllocator.
This scheme is complex, inconsistent, and makes refactoring SDNodes
fairly difficult.
Instead, we can allocate all of the operands using an ArrayRecycler
that wraps a BumpPtrAllocator. This keeps the cache locality when
iterating operands, improves locality when iterating SDNodes without
looking at operands, and vastly simplifies the ownership semantics.
It also means we stop overallocating SDNodes by 2-3x and will make it
simpler to fix the rampant undefined behaviour we have in how we
mutate SDNodes from one kind to another (See llvm.org/pr26808).
This is NFC other than the changes in memory behaviour, and I ran some
LNT tests to make sure this didn't hurt compile time. Not many tests
changed: there were a couple of 1-2% regressions reported, but there
were more improvements (of up to 4%) than regressions.
llvm-svn: 262886
The placement new calls here were all calling the allocation function
in RecyclingAllocator/Recycler for SDNode, instead of the function for
the specific subclass we were constructing.
Since this particular allocator always overallocates it more or less
worked, but would hide what we're actually doing from any memory
tools. Also, if you tried to change this allocator so something like a
BumpPtrAllocator or MallocAllocator, the compiler would crash horribly
all the time.
Part of llvm.org/PR26808.
llvm-svn: 262500
This was causing assertions later from using the wrong pointer
size with LDS operations. getOptimalMemOpType should also have
address space arguments later.
This avoids assertions in existing tests exposed by
a future commit.
llvm-svn: 261580
I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outside ilist_iterator.
Since they depend on getNodePtrUnchecked(), they indirectly rely on UB.
This commit removes all uses of these operators. (I'll delete the
operators themselves in a separate commit so that it can be easily
reverted if necessary.)
There should be NFC here.
llvm-svn: 261498
The code change is simple enough: instead of attaching an anonymous SDLoc to splatted
vector constants, use the scalar constant's existing SDLoc since that is what is passed
into getConstant() as a param. But this changes instruction scheduling, so I'll explain
why that happens.
The motivation for this patch starts near:
http://reviews.llvm.org/rL258833
...x86's getZeroVector() could be similarly cleaned up and I thought it would be 'NFC'.
But when I made that change locally, several x86 codegen tests wiggled.
It turns out that the lack of SDLoc consistency in getConstant() changes the way
ScheduleDAGRRList behaves. This is because the SDLoc contains 'IROrder' and some DAG
scheduler algorithms use IROrder for tie-breaking.
Differential Revision: http://reviews.llvm.org/D16972
llvm-svn: 260582
I reinvented this functionality in http://reviews.llvm.org/D16828 because it was
hidden away as a static function. The changes in x86 are not based on a complete
audit. I suspect there are other possible uses there, and there are almost certainly
more potential users in other targets.
llvm-svn: 260295
This patch consists of two parts: a performance fix in DAGCombiner.cpp
and a correctness fix in SelectionDAG.cpp.
The test case tests the bug that's uncovered by the performance fix, and
fixed by the correctness fix.
The performance fix keeps the containers required by the
hasPredecessorHelper (which is a lazy DFS) and reuse them. Since
hasPredecessorHelper is called in a loop, the overall efficiency reduced
from O(n^2) to O(n), where n is the number of SDNodes.
The correctness fix keeps iterating the neighbor list even if it's time
to early return. It will return after finishing adding all neighbors to
Worklist, so that no neighbors are discarded due to the original early
return.
llvm-svn: 259691
Matt Arsenault